Mill for dispersion and mixing



Aug. 15, 1939. Mi W D|TT0 2,169,339

MILL FOR DISPERSION AND MI'XING Filed July l2, 1938 3 Sheets-Sheet 1 Aug.. 15, 1939. M. w. DITTo MILL FOR DISPERSION AND MIXING Filed July l2, 1938 I5 Sheets-Sheet 2 www ug. 15, 1939. M. w DVI-T0 y 2,169,339

N AND MIXING I Filed July l2, 1938 3 Shee'cS-Sheekl 3 Patented Ang. l5, 1939 Y UNITED STATES PATENT oi-FicE MnLroa msvmmmo l e Marvin w.

This invention relates to into various substances. One of the objects of Gas Fuel Corporation,

mit, New York, N.

Y., assigner to NewYork, N. Y., a

corporation of Delaware IApplication July l2, 1938, Serial No. 218,883

:Z1-Claims. an oil aquolysis mill,

at is a mill for incorporating water or the like the invention is to provide an improved mill for use in very high speed and high pressure work and dispersion is .require Another object of the in where extremely ne vention is to provide a novel mili available for all kinds of work requil-ing dispersion of liquids within each other as well as the incorporation of finely divided pigments, powders, e pounding of chemicals I actions; the .preparation In the drawings: Fig. 1 is a in elevation of one-half of compounds; the dispersion of ba the preparation of colloidal st diametrical sectional vi tc. in liquids; for conito speed up chemical repharmaceutical cteria in serunxs; arch; the prepay such as starch hine is in motion or objects outlined and ew partly the .machine Fig. 2 is a similar view ofthe other half.v

Fig. 3 is a transverse vertical sectional view of the machine Referring to the drawings,

taken on the 1l Fig. 4 is a similar view o1' ne 3-3 of Fig. 1. the machine taken evation of one end of the isa similar view` of .the Oppo- 1 designates'a hollow cylinder having a small portion l and a larger portion 9 with an internal annular shoulder Il arransedcat the line of the juncture.

'I'he ends vof the cylinder are closed by plates H and i2, secured to the 50v by any suitable means, such as to provide a fluid-tight ends of the cylinder` l (as screws I3 so structure.

A rotatable shaft I4 extends axially through l the cylinder and through end plates; each hub formin s; packing rings I6 are arra the hubs ii of the g a chamber in which nged and held com- I other. This is iorfthe purpose of locking a cup tioned in the cup and they ci. 259-9) pressed by glands I1, screwed into the hubs of the end plates.

The end plate Il is provided withan external extension Il forming a support for a bearing structure I9 including an anti-friction bearing 29 in which the shaft is axially and rotatably movable. y

The shaft may be driven by any suitable means connected with its end portion 2i.

The end plate IZ is also provided with an ex-A ternal extension 22, a portion ci which forms a hollow cylinder 28, longitudinally slit at l Where the slit is positioned, the cylinder 23 is provided with internal screw threaded ears 25 to cooperate with a screw 2S provided with a handle 2.

cylinder to move toward or 28 to the cylinder or for l allow it' to be rotated. The cup has a threaded tate the turning of the cup Oppositely disposed anti-friction bearings 3i and 32 preferably of the thrust type are posiare retained in place latter being screwed into into the cup through packing means 35, and a nut 36 and shoulder 31 on the shaft lock the inner race rings 38 to the shaft so that the shaft will be forced to move endwise whenever the hand wheel 30 is rotated. A rotor 39 is positioned on and rotates with such rotor 40 engagement with the shaft.

A'series of imperforate annular ilanges 44, IS, and 41 of progressively increasing diameters, from the end plate II toward the end plate IZ,

flanges (4,15, I6 and 41. Each flange and its associated wall forms a cup, the wallA of which is provided with lengthwise slots I2, 53, il and I5.

yThe wall 4l axial with t 49, and Il nare toward the end plate l2 and g diameters. Each of the walls I9, 50 and 5| is also provided at the mouth of the cup with an imperforate annular inwardly extending flange 56 which function as baffles to cause fluid entering their associated cups to travel inwardly toward the tube 40 before entering the cups.

A stator 51 is positioned in the cylinder 1 between such cylinder and the rotor, and such stator is of tubular form having .portions 58, 59, 60 and 6l conforming to the external shape of the-walls 48, 49, 5U and 5l and arranged in close proximity to the external surfaces of these walls.

The stator is also provided with lengthwise slots 62, 63, 6l and 65, and it 'will be obvious that the distance between the slots of the rotor and the slots of the stator can be varied by turning the wheel 30.

The statortube is held in position by the end plates Il and l2 against which it abuts, and annular imperforate bailies 66, 61, 68 and 69 which are arranged in spaced relation between the cylinder 1 and the stator, divide such space into a series of annular chambers 10, 1|, 12 and 13. Ports 10a place the chambers 10-13 in communication with the interior of the rotor. The baffles 66-69 may be fixed to the stator, and when the stator is introduced into the cylinder 1 through the end closed by the plate l2, the baille 68 will come into engagement with the shoulder IB so as to stabilize the stator.

An inlet 1I leads into the cylinder near the plate Il and discharges into an annular chamber 15, and fluid introduced in this way passes through slots 16 in the stator before entering the first cup M, I8. It will then travel in zigzag paths through the slots in the cups and stator, and of course, will be constrained to move in this way due to the baffles 66, 61, 56, 68 and 69. When the fluid finally reaches the chamber 13 it can pass through slots 11 in the stator and eventually be discharged through an outlet nipple 1B positioned near the end plate l2.

In order that the temperature of the fluid being treated may be regulated, the cylinder 1 is surrounded by a jacket 19 so as to form an annular chamber 80 between the cylinder and jacket. A heating or cooling fluid can be introduced into such chamber through inlet nipple 8| and be discharged through an outlet nipple 82.

As best shown in Fig. 3, the slots 52-55 of the rotor are of V-shape with the points of the Vs directed counter-clockwise, and the slots 62-65 of the stator are of similar shape with the points directed in a clockwise direction. In other words, the V-shaped slots of one are directed in a direction opposite to the slots of the other so that fluidY passing through the slots is subjected to violent impacts. i

In my pending application Serial No. 196,780, I have disclosed V-shaped slots arranged in discs positioned at right angles to the axis of the shaft Y of the rotor with the flow of liquid parallel to such axis. Inthe present invention with the V slots cut in the walls of the cups and the stator tube, the now of the liquid through the slots is at right angles to the axis of the shaft instead of parallel, and the motion is imparted -to the liquid by the slots being substantially parallel to the axis of the shaft. The same principle of impact and shearing takes place in this improved design, i. e., the liquid coming into each rotating cup'is forced at right angles to the axis of the shaft out into the V-slots of the stator and in so doing is reversed in direction twice. In other words, the slots of the rotor cup act to scoop Yprogressively builds up because no 'the liquid and then to cause it to impact at the angle of the slots and to then reverse the direction of fiow before the fluid enters the inlet of the slots of the stator in reverse direction and, of course, each slot of the stator causes the fluid to reverse its direction before it is discharged from such slot.

Efforts in the past have utilized rotating surfaces where the relation of the speed of the respective surfaces was high. Dispersion by the method disclosed herein incorporates an entirely different principle. Instead of depending upon smashing into the solution with a rotating element and changing the direction of fiow by impedance of either an oppositely rotating member or a stationary one, this principle incorporates the theory that the liquid is trying to catch up or build up the same velocity as the passageway through the rotating cylinder. This is practically impossible because the rate of feed or flow of the liquid through the slots is slower than the velocity of the cylinder through which the slots are cut. Therefore, there is a difference in velocity or ratio of speed between the liquid and the slot, and as the only point of outlet for the liquid is through the slot of the stator, liquid passing through the rotor is forced to be stretched, sub-divided and sheared before a successful escape is possible. The velocities are slowed down from each stage or zone of the machine and speeded up again in the succeeding zone as the diameter of the rotating cups and the diameter of the rotor wall increases. The relative velocity more liquid can be discharged from the outlet 18 than is admitted through the inlet 1I. This has a tendency, because of increased certrifugal force, to stretch the liquid further, or that being impossible, to increase its velocity and handle smaller quantities per slot in the larger diameters of the rotor and stator. As the leading points of the discharge of the slots in the rotor can be moved to or from the leading edges of the slots in the stator, it can be readily understood that if particles are ofv larger size than can easily pass through the clearance between the rotor and stator, they will be crushed, cut in two or otherwise deformed during the period of time of passage between the two members.

This principle is very important especially when incorporating finely divided solid material into substances suchas oil or vcolloidal mixtures of starch or the admixture of carbon black, antimony oxide, selenium or titanium oxide in rubber which has been dissolved in a solvent such as benzene.

It is also important to break down the yeast cell during the fermentation period in the manufacture of beer so that the core or center of the yeast cell is exposed to the solution. This problem requires extremely line dispersion of the smashing of the yeast cell in order to speed up the period of manufacture and to smash or break up the yeast cells to increase the rate of reaction. As these yeast cells are microscopic in size and are floating in a liquid body of very low viscosity, the reaction is dependent upon the speed at point of transfer in order to break down the maximum number of cells per unit of time.

This milihas the characteristics of producing colloidal mixtures and emulsions of widely different types of material suc'n as oiland water, cut back rubber and water, residual pitches, wet starch cellulose in the liquid phase, etc., without the use o f emuisifying agents to produce stathis is undesirable bilizednon-segregating mixtures. 'I'hese emulsions become stable because the component 'elements become surrounded with scopic films around the individual globules and due to the difference insuperficial tension have sufficientk strength to. remain in .the stabilized form.

Practice in the past has demanded the use of emulsfying agents in order to stabilize emulsions. The physical reactions taking place within the mill herein described disperse and subdivide the various elements so finely that they remain in the stabilized condition without the use of emulsiers. Most 'of the emulsifying agents have some chemical reaction upon substances to be emulsied and in many instances because it destroys the characteristic of the end product.

Chemical reactions can AVbe speeded up because if a solid is to be dissolved by an acid or alkali the more finely dispersed the solvent is among thematter to be dissolved the more rapid the reaction can take place. This is'due to the fact that the maximum amount of surface of the solid is exposed to the maximum amount of solvent to be used in aunit of time. It is also possible-with mills of this type to put into the solution suchv products as liver like rubber in the' presence of its solvents lsuch as solvent naptha, benzene or the like, in a very short period of time because of the rapid dispersion and dissemination due to the subdividing of the rubber substance sothatv a large amount of solvent can attack a smaller amount of jelly like rubber.

The operative condition may require that there be a minimum of /ooo of an inch clearance between the outer vface of the rotor and the inner surface of being transformed into a work to be done. is considered important that such a machine be adjustable to compensate for different characteristics of material handled as well as wear on the machine.

I wishit particularly understood that my improved mill herein described and illustrated is in the fform which I desire to construct it and that changes and variations may be made as may be convenient or desirable withoutA departing from the salient features of my invention, and I therefore intend the following claims to cover such modifications as naturally fall within the lines of the invention.

-What I claim and desire to secure by Letters Patent is:

1. In a machine of the character described, a rotor member provided. with .an annular wall having to the outer surface of such wall.

minute microthe stator, as the machine dethe Vfs of said slots j a rotor member perpendicular to tor and means for adjusting one' of said mem' a rotor member provided with an annular wall having slots extending lengthwise thereof and of substantially v th'e wall to the outer surface thereof, the plane of the Vs of said slots being perpendicular to the axis of rotation of the rotor and a stator member having an elongated annular wall surrounding the rotor wall and arranged in close proximity to the latter, the wall of the stator member being also provided with slots opposed to the slots ofthe rotor member and of irregular shape from the inner surface of the annular wall of the stator member to the outer surface of such wall.

3. A'machine of the character described a rotor member provided with an annular wall ,having slots extending lengthwise thereof, each slot having opposite walls of substantially V- shape to form a V-shape passageway through the wall extending from its inner to its outer surface, .and a stator member having an annular wall arranged in close proximity to the wall of the rotor member, the wall of the stator member being also provided with slots opposed to the slots of the rotor member, the opposite walls of each slot of the stator being of substantially, V-shape and forming passageways through the stator member with the points of the Vs of the stator extending in a direction opposite to the points of the Vs of the slots of the rotor, the plane of the Vs of said slots being perpen lcular to the axis of rotation of the rotor.

4. In a machine of the character described,

a rotor member provided with an annular wall having slots extending lengthwise thereof, and.

annular wall/arthe walls of the with a stator member having an ranged in close proximity to rotor member, said walls being provided shape from the inner surface of opposed lengthwise slots, the walls of each slot being of V-shape and the points ofthe Vs of the rotor wall being directly opposite to the points of the Vs of the stator wall, the plane of the Vs of said slots being perpendicular to the axis of rotation of the rotor. 5. In a machine of the character described, a rotor member provided with a flared annular wall, a stator member having an elongated, flared annular wall arranged in close wall of e rotor member and flared in the sam'e direction, "said walls being provided with opposed substantially V-shapedslots, the plane of being perpendicular tothe axis of rotation of the' rotor and means for adjusting one of said members axially of the rotor and relatively to the other member to vary the clearance between said walls and theeifective length of the slots.

6. In a machine of wall, a stator member having a flared annular wall arranged in close proximity to the wall of the rotor memberam. flared in the same direction, said walls being prctidedwith opposed slots.

the walls of each slot being of V-shape from the inner surface to the outer surface of the'wall and forming V-shaped passageways through the walls, the plane of the Vs of said slots being the axis of rotation of the robers axially of other member to walls.

7.-'In a machine of the character described, a rotor having an annular wall` including a flared portion, a stator the rotor and 'relatively to the vary the clearance between'. said having an elongated annular` proximity to the the gharacterdescribed, 'I provided with a flared annular opposed slots extending wall provided with a flared portion surrounding the flared portion of the wall of the rotor and arranged in close proximity to the latter, said flared portions being provided with opposed substantially V-shaped slots, the plane of the Vs of said slots being perpendicular to the axis of rotation of the rotorV and means for adjusting the rotor axially of the stator to vary the clearance between .the flared portions of said walls.

8. In a machine of the character described, a rotor having an annular wall including a flared portion, a stator having an annular wall provided with a flared portion surrounding the flared portion of the wall cf the rotor and arranged in close proximity to the latter, said flared portions being provided with opposed slots, and means for adjusting the rotor axially of the stator to vary the clearance between the flared portions of said walls, the walls of each of said slots being of V-shapefrom the inner surface to the outer surface of the wall through which it extends, the point of the V of each slot being positioned substantially midway between the inner and outer surfaces of the wall in which it is arranged.

9. In a machine of the character described, a rotor member having a cup provided with an annular wall, and a stator member having an annular wall arranged in close proximity to the wall of said cup, the walls being provided with lengthwise thereof, the opposed walls of each slot being of substantially V shape from the inner surface to the outer surface of the wall in which the slot is arranged, the point of the V of each slot being positioned substantially midway between the inner and outer surfaces of the wall in which it is arranged.

10. In a machine of the character described, a rotor member having a cup provided with an annular wall, a stator member having an annular wall. arranged in close proximity to the wall of said cup, the walls being provided with opposed lslots extending lengthwise thereof, the opposed walls of each slot being of substantially V shape from the inner surface to the outer surface of the wall in which the slot is arranged, the point of the V of each slot being positioned substantially midway between the inner and outer surfaces of the `avall in which it is arranged said walls being both flared in the same direction, and `means for axially adjusting the rotor relatively to the stator to vary the clearance between the flared portions of the walls.

ll. In mills for dispersion and mixing, a cylinder having closed ends, a shaft rotatably mounted in the cylinder, a rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wall portion provided with' slots extending lengthwise thereof, a stator surrounding the rotor and having an elongated tubular wall with its inner surface in close proximity to the wall portions of the cups, the wall 0f the stator having slots opposed to the slots of the wall portions of the cupsof the rotor, means for admitting a fluid into one end portion of the cylinder and for4 discharging it from the opposite end of the cylinder, and baffles in the cylinder for causing the fluid in passing through the cylinder to travel successively through the slots of the cups and stator.

12. In a machine for dispersion and mixing, a cylinder having closed ends, a shaft rotatably mounted in the cylinder, a rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wallA portion provided with slots extending lengthwise thereof, a stator surrounding the rotor and having an annular wail with lts inner surface in close proximity to the wall portions of the cups, the wall of the stator having slots opposed to the slots of the wall portions of the cups of the rotor, means for admitting a fluid into one end portion of the cylinder and for discharging it from the opposite end of the cylinder, and baffles in the cylinder for causing the uid in passing through the cylinder to travel successively through the slots of the cups and stator. opposed walls of each slot of the wall portion of one of the cups being of irregular shape from the inner surface to the outer surface of such wall portion.

13. In a machine of the character described, a cylinder having closed ends, a shaft rotatably mounted in the cylinder, a rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an vannular wall portion provided' with slots extending lengthwise thereof, a stator surrounding the rotor and having an annular wall with its inner surface in close proximity to the wall portions of the cups, the wall of the stator having slots opposed to the slots of the wall portions of the cups of the rotor, means-for admitting a fluid into one end portion of the cylinder and for discharging it from the opposite end ofthe cylinder, and baffles in the cylinder for causing the fluid in passing through the cylinder to travel successively through the slots of the cups and stator, opposed walls of each slot of the wall' portion of one of the cups being of V-shape and forming V-shaped passageways extending from the inner surface of said wall portion to its outer surface, the point of the V of each slot being positioned substantially midway between the inner and outer surfaces of the wall in which it is arranged.

14. In a machine for dispersion and mixing,

i a cylinder having closed ends, a shaft rotatably mounted in the cylinder, a rotorl mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wall portion provided with slots extending lengthwise thereof, a statorsurrounding the rotor and having an annular wall with its proximity to the wall portions of the cups, the wall of the stator having slots opposed to the slots of the wall portions of the cups of the rotor, means for admitting a fluid into one end portion of the cylinder and for discharging it from the opposite end of the cylinder, and baffles in the cylinder for causing the fluid in passing through the cylinder to travel successively through the slots of the cups and stator, opposed. walls of some of the slots of. the stator being of irregular' shape from the inner surface of the wall of the stator to the outer surface of such wall.

l5. In a machine of the character described, a cylinder having closed ends, a shaft rotatably mounted in the cylinder, a rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wall portion provided with slots extending lengthwise thereof, a stator surrounding the rotor and having linner surface in close an annular wall with its inner surface in close proximity to the wall portions of the cups, the wall of the stator having slots opposed to the slots of the wall portions of the cups of the rotor, means for admitting a fluid into one end portion of the cylinder and for discharging it from the opposite end of the cylinder, and baf- Iles in the cylinder for causing the fluid in passing through the cylinder to travel successively through the slots of the cups and stator, each of said slots forming a V-shape passageway extending from the inner surface to the outer surface of the wall in which the slot is arranged, the point of the V of each slot being positioned substantially midway between the inner and outer surfaces of the wall in which it is arranged.

16. In a machine for dispersion and mixing, a cylinder having closed ends, a shaft rotatably mounted in the cylinder, a rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wall portion provided with slots extending lengthwise thereof, a stator surrounding the rotor and having an annular wall with its inner surface in close proximity to the wall portions of the cups, the wall of the stator having slots opposed to the slots of the wall portions of the cups of the rotor, means for admitting a fluid into one end portion of the cylinder and for discharging it from the opposite end of the cylinder, and bafiles in the cylinder for causing the fluid in passing through the cylinder to travel successively through the slots of the cups and stator,` said wall portions of the cups being flared in the direction toward the outlet of the cylinder and progressively increasing in size, the wall of the stator along such Wall portions of the cups conforming in shape thereto, and means for moving one of said members relatively to the other to vary the clearance between the flared wall portions of the cups and the wall of the stator.

17. In a machine of the character described, a cylinder having, closed ends, a shaft rotatably mounted in the cylinder', a rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wall portion provided with slots extending lengthwise thereof, a stator surrounding the rotor and having an annular wall with its inner surface in close proximityto the wall portions of the cups',the wall of the stator having slots opposed to the slots of the wall portions ,of the cups of the rotor, means for admitting a fluid into one end portion of the cylinder and for discharging it from the opposite end of the cylinder, bales in the cylinder for causing the fluid in passing through the cylinder to travel successively through the slots of the cups and stator, said wall portions of the cups being flared in the direction toward the outlet of the cylinder and progressively increasing in size, the wall of the Astator along such wall portions of the cups conforming in shape thereto, means for moving one of said members relatively to the-other to vary the clearance between the flared wall portions" of the cups and the wall of the stator, the lastmentioned means comprising an extension at one end of the cylinder, a cup adjustably mounted on said extension, an anti-friction bearing' arranged in the last-mentioned cup and in which a portion of the shaft is journalled, and means for constraining the shaft and rotor to move axially with said cup.

18. An apparatus for dispersion and mixing, comprising a hollow cylinder, plates closing the ends of the cylinder, a rotatable shaft extending through the cylinder, arotor mounted on the shaft and comprising a series of cups of progressively increasing size from one end of the cylinder toward the other, means for introducing a fluid into the end of the cylinder where the smallest cup is arranged, means for discharging such fluid from the end portion of the cylinder where the largest cup is arranged, each of said cups being provided with a wall portion and such wall portions flaring toward the outlet end of the cylinder from the first cup to the last one of the series, an elongated tubular stator arranged in the cylinder and surrounding the rotor, the wall portion of each cup and the stator being provided with opposed slots through which the fluid can ow through a cup and then through the wall of the stator, and means in the cylinder for constraining iluid entering the interior to pass progressively throughthe wall portions of the cups and several times through the stator before being discharged through said outlet.

19. An apparatus of the character described, comprising a hollow cylinder, plates closing the ends of the cylinder, a rotatable shaft extending through the cylinder, a rotor mounted on the shaft and comprising a series of cups of progressively increasing size from one end of the cylinder toward the other, means for introducing a iluid into the end of the cylinder where the smallest cup is arranged, means for' discharging such fluid from the end portion of the cylinder 'where the largest cup is arranged, each of said cups being provided with a wall portion and such wall portions flaring toward the outlet end of the cylinder from the first cup to the last one of the s-eries, a stator arranged in the cylinder and surrounding the rotor, the wall portion of each cup and the stator being provided with opposed slots through which the fluid can flow through a cup and then through the wall of the stator, means in the cylinder for constraining fluid entering the interior to pass progressively through the wall portions of the cups and several times through the stator before being discharged through said outlet, and means forming a bearing for said shaft and adjustable axially of the shaft for moving the rotor lengthwise relatively to the'stator for varying the clearance between said flared wall portions of the cups and the wall of the stator.

20. In a machine of the character described, a rotor member provided with an annular wall having slots extending lengthwise thereof and of substantially V shape from the inner surface of the wall to the outer surface thereof, a stator member having an annular wall arranged in close proximity to the wall of the rotor member, the wall of the stator member being also provided with slots opposed to the slots of the rotor member and of substantially V shape from Ithe inner surface of the `annular wall of the stator member to the outer surface of such Wall, the point of the V of each slot being positioned substantially midway between the inner and outer s'urfaces of the wall in which it is arranged means for axially adjusting one of said members relatively to the other, the edges of the walls of the slots being of such conguration as to remain parallel to each other regardless of the operative position of the adjustable member relatively to the other member.

21. In a machine of the character described,

a cylinder having closed ends, a shaft rotatably mounted in the cylinder, an elongated rotor mounted on the shaft and provided with a series of cups arranged successively from end to end of the cylinder, each cup having an annular wall portion provided with slots attending lengthwise thereof. the opposed walls of each slot being of substantially V-shape from the inner surface to the outer surface of the wall portion in which it is arranged. a stator surrounding the rotor and having an elongated tubular wall with its inner surface in close proximity to the wall portions of the cups, the wall of the stator having slots opposed to the slots of the wall portions of the cups of the rotor, the walls of each slot of the stator being of substantially V-shape with the points of the Vs pointing directlyv opposite to the points of the Vs of the slots of the rotor, the point of the V of each slot being positioned substantially midway between the inner and outer surfaces of the wall in which it is arranged means for admitting a fluid into one end portion of the cylinder and for discharging it from opposite end of the cylinder. and haines in the cylinder for causing the fluid in passing through the cylinder to travel in a zigzag path successively through the slots of the cups and stator.

MARVIN W. DI'I'IO. 

